The present disclosure may find many applications, and these applications may not be limited to the food industry. However, for easy description, the disclosure will be described in relation to its application for use in the food industry. In the following description, the terms “casing”, “food product” and “netting” shall have the following meanings:                a. “casing” any synthetic or natural tubular material, or material of any shape, used to wrap processed food,        b. “food product” any fresh or processed food products, and in particular fresh or processed meat products, and        c. “netting” any knitted, woven, extruded or otherwise manufactured packaging netting which is elasticated, rigid, substantially inextensible, laterally extensible and/or longitudinally extensible.        
In the manufacture of food products, and in particular in respect of the manufacture of meat products, natural or artificial casings in the form of elongated tubes are normally either pumped full of meat from a machine specifically designed for the purpose, or have portions of meat placed within the tube prior to either a cooking or a curing process taking place. In some cases, machines dealing with whole meat portions, emulsified or minced meat products use a feed mechanism for injecting meat through a delivery tube or injection horn where the casing is shirred onto the external surface of the delivery tube. A clip or other closure means is placed over the end of the casing, and a quantity of meat is then injected into the casing. Depending on the desired length of the meat product, the process is interrupted at various stages so that clips or twists may be applied to form separate and individual meat product portions.
In addition, whole meat portions may be inserted within tubular casing or netting and, in this instance, stuffing tubes or horns are also used which enables the tubular casing to be stretched, whereupon meat portions can be readily introduced within the tubular casing. In some cases, artificial skins such as collagen-based casings, fibrous casings, or knitted tubular casings have a tubular net or netting placed over the outside of the collagen once the food product is located within the casing. Alternatively, the food product may be inserted directly within the netting without the use of any inner casing. In any case where netting is used, the netting may be shirred onto the external surface of the delivery tube and be dispensed as the meat portions are introduced into the netting.
In some instances, the netting is used primarily for decorative effect and remains in place prior to consumption of the food product. However, in addition to providing a decorative effect, the netting, if properly sized, can be used to produce a surface pattern effect. In this instance, the longitudinal and transverse members of the net apply a force to the surface of the meat product and, provided that the surface of the food product is sufficiently resilient, then the netting will protrude into the surface of the food product. This results in a quilt-like surface pattern, where the longitudinal and transverse members press into the surface of the food product so that the food product bulges outwardly within the square, rectangle or other shapes formed by the longitudinal and transverse members.
In addition to the appearance, the netting may be used to apply pressure for binding. This is where meat pieces have been treated to produce a sticky exudate and multiple pieces are placed within the netting which assists in binding the meat pieces together to form a single meat portion. It is also desirable, particularly in relation to the cooking or curing process, to maintain a desirable shape, and to apply constant compressive force to the meat product during the cooking or curing process. The constant pressure ensures that air pockets do not readily form within the meat, as this may lead to spoilage or unsightly appearance once sliced. It is also desirable to ensure that, particularly during a process where the meat product is hung to cure, no elongation or stretching of the meat product occurs. It is desirable therefore, to hold the meat pieces together from two directions i.e. apply pressure both longitudinally and laterally.
In some instances, during a curing process, the weight of the meat product can cause the netting to stretch, thus resulting in a conical or tapered section from the hanging point to the beginning of the meat product. In many instances, depending on the type of the meat product, a small conical section of meat can be formed at the upper end. This particular section tends to be unsightly when the netting is removed, and is normally cut away and wasted. Alternatively, if the ends are used, there is poor sliceability due to variation in shape.
This problem results from the fact that elastic netting is normally non-elastic (or inextensible) in the longitudinal direction. Only the circumferential members, which form a continuous spiral, are normally formed from elastic material. The longitudinal members are formed from conventional chain stitching. Apart from the normal stretch which results from the knitting process, the netting is generally inextensible in the longitudinal direction. Accordingly, as there is no longitudinal elasticity, stretching and thinning at the upper end of the netting will occur during the curing process.
Further, as the continuous spiral is a single strand, or in some cases multiple strands, of elastic thread, the overall extensibility of the net is limited. Accordingly, the net will be made for a target size that provides a suitable compressive force to a meat product of the target size. However, for meat products that are smaller, the net will be baggy and not provide a suitable indentation on the surface of the meat product. For meat products that are larger, the net may not fit around the meat product. Further, even if the net does fit over the meat product, most meat products taper at one or both ends which means the net will be baggy and not provide suitable indentation at the tapered portion. Finally, as only the circumferential members are formed from elastic material, the compressive forces applied to the meat product produce a mild and superficial imprint upon the surface of the meat product.
To address these problems, the applicant developed a fully elastic netting as described in AU 2014202014 titled “An Openwork Fabric” in which the netting was elastically extensible in both the longitudinal and transverse directions to provide improved indentation upon the surface of the meat product (as the elastic threads impart a deep indentation in the meat surface).
Whilst the fully elastic netting can provide deep indentation the presence of longitudinal elastic threads can present problems when dispensing the netting. Initially, the netting is dispensed freely from the delivery tube. However, as the netting is dispensed over a growing length of the delivery tube, a longitudinal tension is applied to the netting. Due to the extensibility of the longitudinal components, this increase in longitudinal tension can stretch the dispensed netting and alter the shape of the meat product within the netting. The tension applied when the net is pulled from the end of the filling tube can be low tension which produces a longer torpedo shape, through to high tension which causes a more spherical shape. This variation in shape between torpedo shapes and spherical shapes is undesirable.
There is thus a need to provide an improved openwork fabric, or at least provide a useful alternative to previous openwork fabrics.